Have a comp scene. Need to use that same comp scene in several moments throughout my animation. But I want to adjust elements within, such as skies, landscapes in a reveal, but keeping most of the main elements within. Though its easy enough to duplicate, but the one main comp remains, and if I alter that, it changes them all. How can I do this without changing, altering the original comp? Copy and past each element (65 or more) into a brand new comp seems the only logical route if possible - and alter from there?

You can duplicate the nested comp in question in the project window -- not in the main comp. Then you have identical and independent comps which you can modify. It's wise to give these duplicates logical & easily-identifiable names.

Then you can duplicate the original nested comp in the main comp, and use the replace footage command to put in the modified comps.

Dave or Mike - could either of you link me to a decent nesting comp tut? Sorry to ask - and I've been away for some time... and as I am getting back to this portion, the tut vids I watch confuse me. I am using only the project window but my work still changes in original. i used to know how to do this... I'm slipping deep into forgetfulness!